Current methods of needle insertion during percutaneous CT and MRI guided procedures lack precision in
needle depth sensing. The depth of the needle insertion is currently monitored through depth markers drawn on the
needle and later confirmed by intra-procedural imaging; until this confirmation, the physicians’ judgment that the target
is reached is solely based on the depth markers, which are not always clearly visible. We have therefore designed an
optical sensing device which provides continuous feedback of needle insertion depth and degree of rotation throughout
insertion.
An optical mouse sensor was used in conjunction with a microcontroller board, Arduino Due, to acquire needle
position information. The device is designed to be attached to a needle guidance robot developed for MRI-guided
prostate biopsy in order to aid the manual insertion. An LCD screen and three LEDs were employed with the Arduino
Due to form a hand-held device displaying needle depth and rotation. Accuracy of the device was tested to evaluate the
impact of insertion speed and rotation.
Unlike single dimensional needle depth sensing developed by other researchers, this two dimensional sensing
device can also detect the rotation around the needle axis. The combination of depth and rotation sensing would be
greatly beneficial for the needle steering approaches that require both depth and rotation information. Our preliminary
results indicate that this sensing device can be useful in detecting needle motion when using an appropriate speed and
range of motion.